json_agg与postgres联合语法错误

Question

我正在尝试执行一个查询，该查询返回一个对象，该对象包含一个列表，该列表已从两个与该对象有很多关系的不同表中合并。

这就是我所做的：

 json_agg((select u.name AS name, u.email AS email
from reports wr
LEFT JOIN 
reportaccountusers rau
ON rau.reportid = wr.id
LEFT JOIN accountusers au
ON rau.accountuserid = au.id
LEFT JOIN users u
ON au.userid = u.id 
where wr.id = 47)
 UNION
(select re.email AS name, re.email AS email
from reports wr
 LEFT JOIN 
reportemails re
ON wr.id = re.reportid
where wr.id = 47)) AS Recipients

但是我做到了，我无法让它真正起作用。

当我这样做时：

select json_agg((select u.name AS name, u.email AS email
from reports wr
LEFT JOIN 
reportaccountusers rau
ON rau.reportid = wr.id
LEFT JOIN accountusers au
ON rau.accountuserid = au.id
LEFT JOIN users u
ON au.userid = u.id 
where wr.id = 47)
 UNION
(select re.email AS name, re.email AS email
from reports wr
  LEFT JOIN 
reportemails re
ON wr.id = re.reportid
where wr.id = 47)) AS Recipients

我收到错误：

错误：“UNION”处或附近的语法错误 第11行：UNION               ^ **********错误**********

错误：“UNION”处或附近的语法错误 SQL状态：42601 性格：283

像这样：

   select json_agg(x) from((select u.name AS name, u.email AS email
from reports wr
LEFT JOIN 
reportaccountusers rau
ON rau.reportid = wr.id
LEFT JOIN accountusers au
ON rau.accountuserid = au.id
LEFT JOIN users u
ON au.userid = u.id 
where wr.id = 47)
 UNION
(select re.email AS name, re.email AS email
from reports wr
  LEFT JOIN 
reportemails re
ON wr.id = re.reportid
where wr.id = 47))x) AS items